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I have purchased the Amazon EC2 m1.medium reserved instance. Now how do I go about creating a root storage volume with 400GB capacity?

By extending the default root 30GB vol to 400GB will be resulting in an extra EBS 400GB which I do not need as the EBS will incur extra charges.

I have done some research saying that the Instance Store Volumes is ephemeral type which is not persistent.

Here's the link ( Will moving data from EBS to ephemeral storage improve MySQL query performance? )

Any advice will be appreciated.

Community
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user1057161
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2 Answers2

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If you boot your instance off an instance store AMI then you'll get your 400G of local instance storage. If you ever shut that instance down you'll lose that data (reboots are ok)

If you use an EBS base ami the root device will always be a EBS volume. If you want the ephemeral volumes to be available this must be specified when starting the instance. You can do this via the web console or by passing a BlockDeviceMapping option when using the various APIs that create instances. Data on the ephemeral volumes is still lost when the instance is shut down.

Frederick Cheung
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  • does that mean the 400GB bundled with the medium instance is never meant to store persistent data? and the only way is to purchase extra EBS storage from amazon? – user1057161 Oct 02 '12 at 08:01
  • You should be in a position to lose that data. That might mean having a copy in EBS (or some other form of storage), or replicated across multiple machines. – Frederick Cheung Oct 02 '12 at 10:56
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user1057161:

does that mean the 400GB bundled with the medium instance is never meant to store persistent data? and the only way is to purchase extra EBS storage from amazon?

Correct. Ephemeral storage is… ephemeral. It is non-persistent by design. Attaching an EBS volume or pushing the data into S3 are the intended ways to persist data.

High scalability (which AWS is designed for) means having lots and lots of cheap servers clustered together — any of which can go belly-up without warning, but that's expected.

If you have a single instance and you're relying on ephemeral storage… don't. The words "rely" and "ephemeral" do not belong together. Plan for instances to go belly-up without warning, and make your application resilient to it.

I hope this helps! :)

Ryan Parman
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